Dylan O'Brien ended up playing drums on Taylor Swift's 'Snow On The Beach' by accident after they were 'drinking wine' in the studio

• Taylor Swift said Dylan O'Brien ended up playing drums on "Snow On The Beach" by accident.
• She told Jimmy Fallon they were in the studio drinking wine when O'Brien started playing the drums.

Taylor Swift told Jimmy Fallon during a Monday appearance on "The Tonight Show" that Dylan O'Brien's drumming credit on her new song, "Snow On The Beach," wasn't exactly planned.

While talking about Swift's new album, "Midnights," Fallon acknowledged that she has collaborated with some "very fun people" on various projects for the album, including O'Brien.

After pointing out her partnership with Lana Del Rey on "Snow On The Beach," Fallon said, "And then I saw on drums — is it Dylan O'Brien?"

Swift confirmed that, yes, O'Brien did play drums for her on track four of "Midnights."

"How is he a drummer even?" Fallon asked. O'Brien is a famous actor, most notably in "Teen Wolf," and he also starred the the "All Too Well (10 Minute Version) (Taylor's Version) (From The Vault)" short film, which was released last fall.

"He is, and not a lot of people know that," Swift told Fallon. "And now they do."

Swift said she was "very lucky" to have collaborated with Del Ray on the song and that O'Brien was in the studio with the pair and Jack Antonoff when they were recording at Antonoff's studio.

"Dylan was just hanging out, drinking wine with us and listening to us," she said. "He wasn't serious."

"That's how it happens," Fallon said.

"As I said, we were drinking wine," Swift continued, "and so we were just sort of like, 'Oh, we haven't recorded the drums for this one yet...' And he just played the drums on the song."

"Sometimes it just happens like that," Swift said.

Swift went on to explain that she became "really close friends" with O'Brien after he starred in the "All Too Well" short film and said they all "hang out all the time."

"I've been very lucky to work with very nice, very talented people. And that's not something I ever take for granted," Swift said. "And a lot of the time, we end up really good friends."

Swift said she loves making things with her friends, noting that "the experience of making something is just as important as how proud you are of it in the end."

She added that it "informs" how proud she is of a project if she had a "really joyful" time creating it, explaining that "Midnights" is a "pretty dark album" but that she had "more fun making it than any album I've ever made."